The study is designed for longitudinal investigation of bone mineral loss and non-violent fractures in a hemogeneous Japanese population in Hawaii, in conjunction with the Honolulu Heart Study and the Japan-Hawaii Cancer Study. This unique, well-studied population is one of exceptional stability and longevity, and also possesses unique social and cultural differences with regard to aging. Bone mineral loss will be assessed over a five-year period using photon absorptiometry, and non-violent fractures will be monitored. Loss of bone mineral will be correlated with multiple personal, social, and dietary characteristics, with special emphasis upon physical activity levels following menopause and retirement. Environmental and genetic factors will be studied by comparison of results with similar studies of Caucasians on the U.S. mainland. Osteoporotic subjects developing non-violent fractures will be compared to osteoporotic subject without fractures in an attempt to define pathologic versus physiologic bone mineral loss. This comparison will include extensive histopathologic examination at autopsy. A final aim is to identify a possible subgroup in a rapid, active stage of bone mineral loss who could prove valuable in a further study of the pathophysiologic mechanisms involved in osteoporosis.